Police say the men walked into the 7-Eleven store at 1801 Pennsylvania Avenue at 11:24 p.m. on New Year's Eve.
One suspect pulled out a handgun, jumped behind the counter and tried to take cash from the register.
When the clerk started dialing 911 on a cell phone, the suspects grabbed the phone and fled.
One suspect is described as a black male, 5'08", thin build. He was seen wearing a gray hooded sweatshirt, baseball cap, and blue jeans.
The other is described as a black male, 5'08", thin build, last seen wearing a black jacket, black pants, and a face mask.
Anyone with information is asked to contact Wilmington Police Detective Joseph Bucksner at 302-576-3629, the Wilmington Police Confidential Tip Line at 302-576-3990, or Delaware CrimeStoppers at 800-TIP-3333 or online at www.tipsubmit.com.